Apparatus for skiving abrasive bands for formation of abrasive belts therefrom



May 21, 1963 A. ACKERMAN 3,090,167 APPARATUS FOR SKIVING ABRASIVE BANDS FOR FORMATION OF ABRASIVE BELTS THEREFROM Filed Sept. 50, 1959 3 SheetsSheet l INVENTOF! ARTHUR ACKERMAN HIS ATTORNEYS y 1, 1963 A. ACKERMAN 3,090,167

APPARATUS FOR SKIVING ABRASIVE BANDS FOR FORMATION OF ABRASIVE BELTS THEREFROM Filed Sept. 30, 1959 5 Sheets-Sheet 2 INVENTOR ARTH U R ACKERMAN Y Fq .i4.uz i M HIS ATTORNEYS May 21, 1963 A. ACKERMAN 3,090,167 APPARATUS FOR SKIVING ABRASIVE BANDS FOR FORMATION OF ABRASIVE BELTS THEREFROM Filed Sept. 50, 1959 3 Sheets-Sheet 3 R N 3 mm j N I N Du E W. I I V IHI IIII Nm I|I.I n rIlr II l|H||||F||L m m I II II fim R I @m I III Mm II h v A al n W Y m A n I A a, T II M m .II R I N M W/ w A MN WN GQ \ml P JHIMHXULWUAIMWQnHA I S 0 I mm n vm m Ev I. m 0 I .I fiFF G III O O m IIIII m.T I I III L .711 42%;... v-M

HIS ATTORNEYS Unite States This application relates to devices for removing abrasive grits from at least one end of an abrasive belt preparatory to joining the opposite ends of the belt to form an endless belt for use in belt sanders and the like.

Heretofore, the abrasive grits bonded to the surface of an abrasive belt were removed from a narrow zone or a band at one end of the belt by a scraping operation. The grits must be removed to enable the ends of the band to be bonded together by an appropriate adhesive with sufficient tenacity to withstand the stresses imposed upon the belt during belt sanding operations and the like. The prior scraping or skiving operation was slow and expensive and did not always provide a joint or seam strong enough to enable prolonged operation of the belts. When the grits are not removed completely, a good bond cannot be obtained between the ends of the belt. When the fabric is scraped or skived too deeply, the textile fabric is weakened. Both of these conditions cause premature belt failure. Moreover, the prior methods produced thickened seams Where the ends of the belts overlapped and were bonded together and these seams were a source of weakness and failure of the belts.

In accordance with the present invention, a machine is provided for removing the abrasive grits at one or both ends of the belt strip with a high degree of accuracy so that the underlying fabric is not damaged or weakened by the removal of the grits therefrom but nevertheless is fully exposed to enable an adhesive to be applied thereto to bond the ends of the strip together to form a strong abrasive belt having long operating life.

More particularly, in accordance with the present invention, a typical machine includes a table for supporting an abrasive coated web and a grinding wheel, such as a diamond wheel, which is mounted for movement across the web to grind the abrasive from a narrow zone of the web which corresponds to one or both ends of a belt or a group of belts. The machine includes controls for precisely regulating the depth of grinding accomplished with the grinding wheel and to compensate for wear of the grinding wheel. It also includes a mechanism for enabling the grinding wheel, when moving in one direction across the web, to remove all of the abrasive grits from a narrow zone and upon return movement to remove only a part of the layer of abrasive grits from an adjacent zone. When the web is cut to form belt strips, one end of each strip has a zone from which all of the grits are removed, while the other end may have a thin layer of the grits. When the ends are joined to form a belt it is of uniform thickness throughout its entire extent including the seam where the ends of the belt are joined.

The new machine operates efficiently and at high speed so that high production rates are achieved. High production rates realized by the invention provide substantial manufacturing economies and enable the belts to be produced at substantially reduced cost.

For a better understanding of the present invention, reference may be had to the accompanying drawings in which:

FIGURE 1 is a plan view of a typical grinding machine for skiving abrasive belts, embodying the present invention;

FIGURE 2 is a front elevational and partial sectional view of the machine;

atent ice , view of the machine; and

FIGURE 4 is an end elevational view of a portion of the machine.

The form of grinding and belt skiving machine illustrated herein includes a supporting platform 10 which may be provided with legs 11 and 12 at its corners to support the platform at a desired level. Mounted on top of the platform 10 is a pedestal 13 of generally rectangular form. As shown in FIGURE 2, the pedestal 13 may be a hollow casting and may be bolted or otherwise secured to the platform 10-. Mounted on the pedestal 13 by means of bolts 15 is a machine base 16 which may be a hollowed-out casting of generally frame like contour and having inwardly extending side members 16a and 17 defining a slot 18 extending generally lengthwise of the machine base frame 16. The slot 18 is disposed on a bias to the platform 10, so that a web of abrasive coated fabric F extending lengthwise of the platform 10 will be disposed on a bias with respect to the axial center line of the slot 18.

Fixed in the slot 18 between the side members 16:: and 17 are a pair of spaced plates 19 and 20. A member 21 of T-shaped cross section is slidably mounted between the plates 19 and 20 and forms a support for the web of fabric F.

A groove 22 is formed in the under surface of the T-shaped support 21 and carries therein a pair of segmental gears 23 and 24 which are fixed to shafts 25 and 26 extending through the support and into the plates 19 and 20. The plates 19 and 20 are provided with circular openings 27 and 28 which receive the discs 29 and 3t) ec-centrically mounted on the opposite ends of the shafts 25 and 26 respectively. When the eccentrics 28 and 29 are rotated in unison, the T-shaped support member 21 is raised and lowered with respect to the side plates 19 and 20. Rotation of the eccentrics is accomplished by means of a rack 31 which is slidably mounted between the plates 19 and 2t and in the groove or slot 22 in the T-sha-ped support. The rack engages the segmental gears 23 and 24. Endwise adjustment of the rack 31 is accomplished by means of the screw threaded shaft 32 which is rotatably mounted in the lefthand end of the machine base 15 as viewed in FIGURE 2 and is threaded into threaded sleeve 33 fixed to an extension 34 at the left-hand end of the rack .31. The shaft 32 is rotated by means of a hand wheel 35- mounted on an offset housing 36 as shown in FIGURE 4. The hand wheel 35 is fixed to and rotates a shaft 37 carrying a sprocket 370 which is connected by means of a chain 37b with a sprocket 33 fixed to the threaded shaft 32. Rotation of the hand wheel 35 thereby rotates the threaded shaft 32 to move the rack 31 lengthwise. A spring 39 bears against the outer end of the sprocket 38 and a nut on the end of the shaft 32 to urge the washer or shoulder 3 2a against the abutment member 40 fixed to the frame thereby eliminating slack from the system and assuring precision adjustment of the rack.

Ventical adjustment of the T-shaped support 21 has a two-fold purpose. First, the adjustment is needed to control the amount of the abrasive coating to be removed from the surface of the fabric F and-second, it compensates for wear of the diamond grinding wheel W. As best shown in FIGURE 3, the grinding wheel W is driven by an electric motor 41 which is mounted on a carriage 42 described hereinafter in greater detail which is movable along a rail 43 supported at its opposite ends on uprights 44 and 45 fixed to the opposite ends of the machine base 15. The uprights 44 and 45 are substantially mirror images of each other. As illustrated in FIGURE 4, the upright 45 has a curved side edge 46 and a notch 47 at the upper end of its opposite edge 48 in which the carriage-supporting rail 43- is mounted.

- As shown in FIGURES 1-3, the carriage 42 includes a rectangular base plate *50 having at one end a framelike member 51 having laterally extending cars 52 and 53 adjacent its upper end. Rollers 54 and 55 are rotatably mounted in the cars 52 and 53 and bear against a wear plate 56 on the upper edge of the supporting rail 43.

A transverse web 57 of the frame 51 also carries rotatably a pair of rollers 58 and 59 which roll against a wear plate strip 60 at the upper edge of the rail 43. Adjustably mounted on the base plate 50 are a pair of rollers 60a and 61 (FIGURE 1) which bear against a wear plate or strip 62 secured adjacent the lower edge of the guide rail 43. In this way, the carriage 42 is stabilized and can move smoothly along the guide rail 43.

The motor 41 and the grinding wheel W are suspended from a plate 63 which carries on its bottom surface a. slide plate 64 having wedge-like camrning surfaces 65 and 66 of small inclination adjacent to its opposite ends. The slide plate 64 rests upon two pairs of rollers 67 and 68 which extend inwardly from the opposite edges of the plate 50. Thus, the motor and the grinding wheel W can be moved axially with respect to the base plate 50 of the carriage 42. As the camming surfaces 65 and 66 engage the rollers 67 and 68 respectively, the motor 41 and grinding wheel W are raised with respect to the carriage 42 and to the web support 21. The amount that the grinding wheel W can be raised for a given endwise movement can be adjusted by providing the slide plate 64 with a rack 69. An adjusting pinion 70 is rotatably mounted on the plate 63 and engages the rack 69 so that the slide plate 64 can be adjusted endwise relative to the motor and the supporting plate 63 by rotation of the pinion 70. A selector 71 fixed to the motor having means thereon for releasable locking engagement with an adjusting lever 72 fixed to pinion 70 permits the slide plate 64 to be adjusted accurately. The motor 41 and grinding wheel W are moved endwise or axially by means of an air cylinder 73 (FIG- URE 3) carried by the carriage base plate 50 and connected by means of a piston rod 74 to an upstanding lug 75 on the motor mount plate 63 and extending through a slot 76 in the base plate 50. Endwise movement of the motor is limited by a threaded stop member 77 mounted in a lug 78 on the base plate 50.

The carriage 42 and the grinding wheel W are moved along the rail 43 by any suitable motor or drive, such as, for example, by means of the air cylinder 89 which has a piston rod 81 connected to the carriage frame 51 (FIGURES =1 and 2). Application of air pressure to opposite ends of the air cylinder 80 alternately will cause the grinding wheel to move back and forth lengthwise of the web support 21.

A further control member for the machine is the air cylinder 82 shown in FIGURE 3 which operates a pair of clamping bars 83 and 84 mounted on arms or plates 85 and 86 carried by the shafts 87 and 88 which are rotatably supported at their opposite ends in the bosses 89 and 90 on the end frames 44 and 45. The shafts 87 and 88 are rocked by means of levers -91 and 92 fixed to the shafts and connected, respectively, to one end of the air cylinder 82 and one end of the piston rod 93 of the air cylinder. The machine may be provided with appropriate protective means such as the grinding wheel guard 95. Moreover, dust shields such as the strips 96 and 97 on the support 21 may be included to protect the operating parts of the machine from abrasive materials.

In the operation of the device, the supporting plate 21 is adjusted into a predetermined spaced relation to the grinding wheel W equal essentially to the thickness of the fabric of the web F. Web F is then pulled into a position so that it overlies the support 21 and is disposed on a bias with respect to the support 21. Air is then admitted to the air cylinder 82 to rock the clamping bars 83 and 34 against the fabric F to hold it against the supporting plate 21. With the motor 41 operating, air is then admitted into the left-hand end of the air cylinder 80 so that the carriage 42 and the grinding wheel W are moved across the fabric F thereby grinding off the abrasive coating throughout a zone of about the same width as the width of the grinding wheel W and extending completely across the fabric F. At the end of the movement of the grinding wheel W to the right, air is admitted to the air cylinder 73 on the carriage 42 so that the motor 41 and grinding wheel W are shifted axially to the right as viewed in FIGURE 3, a distance about equal to the width of the grinding wheel. With the camming surfaces 65 and 66 on the slide plate 64 in the position shown, such a movement of the motor to the right will raise the grinding wheel slightly, for example, about the thickness of the fabric F. Air is then admitted to the right-hand end of the cylinder so that the carriage is moved to the left along a path parallel to the path followed during its movement to the right. As a result, a part of the layer of abrasive grits is removed during the return movement of the grinding wheel to the left. At the end of the movement of the wheel to the left, air is admitted to the right-hand end of the air cylinder 73 thereby shifting the abrasive wheel of the motor back to its starting position and air pressure is exhausted from the cylinder 82 thereby releasing the fabric P so that it can be moved through a cutter (not shown) where the fabric is out along a line between the two zones from which the grits have been completely and partially removed. In this way, one end of the resulting fabric strip has all of the abrasive grits removed from a narrow zone at one end while its opposite end has only a part of the thickness of the layer of abrasive grits removed therefrom. When the two ends of the belt are brought into overlapping relation and bonded together by means of an adhesive, the thickness of the seam is equal to the thickness of the belt elsewhere between its ends.

It will be understood that the grinding wheel can be adjusted by means of the adjusting arm 72 to remove a greater or lesser amount of the abrasive coating from the fabric, depending upon the requirements. Thus, the machine may be adjusted so that in both its right-hand and left-hand strokes all of the abrasive coating is removed from the fabric. Likewise, the machine can be adjusted so that on the right-hand stroke all of the abrasive coating is removed from the fabric while on the return stroke none of the abrasive coating is removed from the fabric.

The machine can be operated manually as described above or it can be provided with an appropriate control system whereby the operations of the machine are automatically controlled. Accordingly, the machine described herein can be adjusted and operated as the purpose demands and that webs of fabric of different widths, corresponding to a plurality of belts, can be skived by means of the machine thereby enabling high production rates to be attained with the machine.

It will be understood that the machine is susceptible to considerable modification in its various components and, accordingly, the form of the invention described herein should be considered as illustrative.

I claim:

1. An apparatus for removing abrasive from portions of an abrasive coated fabric for the formation of abrasive belts therefrom comprising a support for an abrasive coated fabric, a motor driven abrasive wheel, means supporting said wheel for movement across said fabric in engagement therewith for grinding at least a part of the abrasive coating from said fabric along the path of said wheel, means for effecting a back and forth reciprocating movement of said wheel across said fabric, and

means for shifting said wheel axially through a distance about equal to the thickness of said wheel at one end of said path and axially in the opposite direction through the same distance at the opposite end of said path and for guiding said wheel along parallel courses at least partially displaced from each other during said back and forth reciprocating movement.

2. An apparatus for removing abrasive from portions of an abrasive coated fabric for the formation of abrasive belts therefrom comprising a support for an abrasive coated fabric, a carriage, means supporting said carriage in spaced relation to said support for movement across said fabric, a motor on said carriage, a grinding wheel on said carriage and driven by said motor, means for effecting a back and forth reciprocating movement of said carriage along said supporting means therefor, means for adjusting said support and said wheel relatively to enable said wheel to engage said fabric and grind said abrasive therefrom along a path extending across said fabric, and means on said carriage for shift ing said wheel axially in one direction at one end of said path and axially in the opposite direction at the opposite end of said path and for guiding said wheel along parallel courses at least partially displaced from each other during said back and forth reciprocating movement.

3. An apparatus for removing abrasive from portions of an abrasive coated fabric for the formation of abrasive belts therefrom comprising a support for an abrasive coated fabric, a guide rail mounted on said support in spaced relation thereto and extending transversely of said fabric, a carriage mounted on said rail for movement lengthwise thereof, a motor-driven grinding wheel mounted on said carriage with its axis substantially perpendicular to said rail, means for adjusting the spacing between said support and said grinding wheel, means for moving said carriage lengthwise of said rail in one direction and lengthwise of said rail in the opposite direction to engage said grinding wheel with said fabric along paths [across said fabric, and means on said carriage for moving said grinding wheel axially in one direction at one end of its path, for moving said grinding Wheel axially in the opposite direction at the other end of its path, and for guiding said wheel along parallel courses at least partially displaced from each other during successive movements in said one and said opposite directions to remove the abrasive coating at least partially from said fabric throughout a zone of a width greater than the thickness of said grinding wheel. 1

4. An apparatus for removing abrasive from portions of an abrasive coated fabric for the formation of abrasive belts therefrom comprising a support for an abrasive coated fabric, a motor driven abrasive wheel, means supporting said wheel for movement across said fabric in engagement therewith for grinding at least a part of the abrasive coating from said fabric along the path of said wheel, means for reciprocating said wheel across said fabric, means for shifting said wheel axially through a distance about equal to the thickness of said wheel at one end of said path and axially in the opposite direction through the same distance at the opposite end of said path, and means for moving said grinding wheel away from said support at one end of its path and toward said support at the opposite end of its path.

5. An apparatus for removing abrasive from portions of an abrasive coated fabric for the formation of abrasive belts therefrom comprising a support for an abrasive coated fabric, a carriage, means supporting said carriage in spaced relation to said support for movement across said fabric, a motor on said carriage, a grinding wheel on said carriage and driven by said motor, means for reciprocating said carriage along said supporting means therefor, means for adjusting said support and said wheel relatively to enable said Wheel to engage said fabric and grind said abrasive therefrom along a path extending across said fabric, and means for changing the spacing between the wheel and said support at opposite ends of said path.

6. An apparatus for removing abrasive from portions of an abrasive coated fabric for the formation of abrasive belts therefrom comprising a support for an abrasive coated fabric, a carriage, means supporting said carriage in spaced relation to said support for movement across said fabric, a motor on said carriage, a grinding wheel on said carriage and driven :by said motor, means for reciprocating said carriage along said supporting means therefor, means for adjusting said support and said wheel relatively to enable said wheel to engage said fabric and grind said abrasive therefrom along a path extending across said fabric, means on said carriage [for shifting said wheel axially in one direction at one end of said path and axially in the opposite direction at the opposite end of said path, and means for changing the spacing between said wheel and said support at opposite ends of said path to remove all of the abrasive from the fabric in the path of said grinding wheel at it moves in one direction across the fabric and to remove only a portion of said abrasive from said fabric in the path of said grinding wheel as it moves in the opposite direction across said fabric.

7. A11 apparatus for removing abrasive from portions of an abrasive coated fabric for the formation of abrasive belts therefrom comprising a support for an abrasive coated fabric, a guide rail mounted on said support in spaced relation thereto and extending transversely of said fabric, a carriage mounted on said rail for movement lengthwise thereof, a motor-driven grinding wheel mounted on said carriage with its axis substantially perpendicular to said rail, means for adjusting the spacing between said support and said grinding wheel, means for moving said carriage lengthwise of said rail to engage said grinding wheel with said fabric along a path across said fabric, means on said carriage for moving said grinding wheel axially in one direction at one end of its path and for moving said grinding wheel axially in the opposite direction at the other end of its path to remove the abrasive coating at least partially from said fabric throughout a zone of a width greater than the thickness of said grinding wheel, means on said carriage for moving said grinding wheel toward said support at one end of said path and away from said support at the opposite end of said path, and means on said carriage for adjust ing the amount of movement of said wheel toward and away from said support.

References Cited in the file of this patent UNITED STATES PATENTS Barclay Aug. 11, 1959 

1. AN APPARATUS FOR REMOVING ABRASIVE FROM PORTIONS OF AN ABRASIVE COATED FABRIC FOR THE FORMATION OF ABRASIVE BELTS THEREFROM COMPRISING A SUPPORT FOR AN ABRASIVE COATED FABRIC, A MOTOR DRIVEN ABRASIVE WHEEL, MEANS SUPPORTING SAID WHEEL FRO MOVEMENT ACROSS SAID FABRIC IN ENGAGEMENT THEREWITH FOR GRINDING AT LEAST A PART OF THE ABRASIVE COATING FROM SAID FABRIC ALONG THE PATH OF SID WHEEL, MEANS FOR EFFECTING A BACK AND FORTH RECIPROCATING MOVEMENT OF SAID WHEEL ACROSS SAID FABRIC, AND MEANS FOR SHIFTING SAID WHEEL AXIALLY THROUGH A DISTANCE ABOUT EQUAL TO THE THE THICKNESS OF SAID WHEEL AT ONE END OF SAID PATH AND AXIALLY IN THE OPPOSITE DIRECTION THROUGH THE SAME DISTANCE AT THE OPPOSITE END OF SAID PATH AND FOR GUIDING SAID WHEEL ALONG PARALLEL COURSES AT LEAST 